In this application, the investigators propose to determine the nucleotide sequence of the genome of Actinobacillus actinomycetemcomitans (hereafter abbreviate Aa for obvious reasons). Aa is the causative agent of localized juvenile periodontitis (LJP), afflicting at least 70,000 children and adolescents each year in the US. LJP is a chronic inflammatory disease of the gingiva (gums) and underlying bony tissues, with no effective prevention. Recent data suggests that Aa is also involved in other periodontal disease syndromes, and causes life-threatening extraoral infections. Taxonomically Aa is closely related to Haemophilus influenzae. This is a highly attractive feature of the Aa genome sequencing project. From the viewpoint of a student of microbial pathogenesis, the H. influenzae genome sequence has several specific problems, despite the singular importance of that achievement. The studies will avoid pitfalls that compromised the H. influenzae database. Indeed, the Aa genomic sequence may enhance the utility of the H. influenzae sequence, in addition to providing important information on Aa. Thus, the investigators propose a single specific aim for the project: to determine and analyze the nucleotide sequence of the 2.2 Mb genome of Aa strain CU1000.